Method of making mercury switches



Au 9, 1932. J. M. FAGAN METHOD OF MAKING MERCURY SWITCHES Filed Aug. 27, 1930 Patented Aug. 9, 1932 UNITED STATES PATENT OFFICE JAMES M. FAGAN, OF MAPLEWOOD, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE LAMP 6 COMPANY, A CORPORATION OF PENNSYLVANIA I iun'rnon or MAKING MERCURY swrrorms Application filed Augustfii, 1930. Serial No. 478,022.

vide a progressive method of evacuating a bulb, introducing an excessive quantit of mercury therein, removing a portion the mercury and filling the bulb with a gaseous environment.

Other objects and advantages of the invention will be more fully understood from the following description together with the accompanying drawing, in which Fig. 1 shows a mercury switch device partly 1n section in loading position on a con-.

veyor for movement for an exhausting operation; 1 e

Fig. 2 shows a bulb in position for exhausting;

Fig. 3 shows the bulb partly in section and in position to receive a quantity of mer-' cur v 4 shows the bulb in position for the.

removal of a portion of the mercury;

. Fig. 5 shows the bulb in position to receive a gas filling,and

Fig. 6 shows the bulb in position for a sealing or tipping ofi operation.

The present invention is practiced for supplying mercury to a mercury switch of the type disclosed in co-pending application Serial No. 477,521 filed August 25,1930, assigned to the same assignee as is the present ap lication.

s shown in Fig. 1 the bulb employed in practicing the present invention may .comprise a lass envelope 10 comprisinga press 11 in w ich is sealed a pair of electrodes 12 and 13. The press 11 is provided with a passageway 14 communicating with an external exhaust tube 15 and with a tubular extension or stand-pipe 16 which latter extends into the bulb or envelope a predetermined distance.

' Mounted on the electrodes 12 and 13 is a refractory element 17 having a cavity 18 in which an end of the electrode 13 is disposed. Leading from the cavity is an inehned surface 19 and the electrode 12 extends into the refractory elementat substantially the. lower end of scribed is provided with; a mercu pool and when the switch is in operation it is tilted so that the pool ofmercury moves tomake connection between the electrodes or to break the connection between the electrodes. It is essential in devices of the present character to provide a definite amount'of mercury in each device. Furthermore it has been found difi'icult to-introduce a quantity of mercury and evacuate the device without drawing out When evacuating the bulb in accordance with the present invention and filling the same with mercury the exhaust tube 15 is inserted into an exhaust rubber 21 of a conveyor 22 of an exhaust machine. The exhaust rubber 21 is connected by means of a tubular conductor 23 with the valve of a vacuum pump (not shown).

the said inclined surface. A mercury switch constructed as above dea part of the mercury into the yacuuin line.

Any suitable, conveyor type vacuum machine may be used .in which a plurality of exhaust ports 24 are employed and which during a movement of the conveyor are successively connected with vacuum pumps for evacuating a hollow vessel as; for example an exhaust conveyor such as that shown in Patent 1,596,733 issued August 17 ,1926, may be 1 used.

After the device is inserted in the exhaust rubber as shown in Fig. 1 it is moved into what may be termed an evacuating position indicated in Fig. 2. In this position the vacy uum pump removes the gas from the tube and the conveyor then moves the device until the conductor 23 is connected with a mercury supply line 25 which leads from a mercury supply tank 26. A valve 27 is provided and a given amount of mercury 28 ispermitted to flow into the'bulb. Asshown the amount ofmercury may be in such quantity as to have a depth greater than the height of the .tubular extension 16. The conveyor may then be moved to connect the conductor 23 with .a tank 29 for'receiving surplus mercury. The tank may be connected Wltll a vacuum line 30 and the mercury in the bulb above ,the level or outlet orifice 31 of the extension 16 will be drawn out leaving a mercury pool 32 with its surface substantially flush with the inner end of the extension 16 thus determining the level of the pool 32.

I After the mercury pool 32 has been intro duced the device may again be evacuated to remove mercury vapors and the conductor 23 may be connected with a suitable gas line to admit a gaseous filling as for example h drogen. The conveyor may then move t e device to a position as shown in Fig. 6 wherein the exhaust tube 15 is disposed between fires 33 and 34 which perform a tipping off operation. At this position jaws 35 and 36 may engage the bulb and as the fires tip off the same the bulb may be removed from the conveyor.

The above method may be practiced for supplying a mercury pool of a definite amount to a device by removing excess mercury. It will be understood, however, that by reason of the tubular extension 16 the bulb may be moved to position as for example Fig. 3 and a definite amount of mercury may be admitted to the device, such amount being so controlled that its depth when in the device will be of a dimension less than the height of the tubular extension. A device so filled may be readily evacuated by an exhaust pump without causing any mercur to fiow into the exhaust line since the out et orifice at the upper end of the tubular extension is above the mercury level a vacuum may be produced in the device without sucking or drawing any of the mercury through the exhaust tube.

The present invention affords a simple and effective method of exhausting and supplymg a mercury switch with a mercury pool and simplifies manufacture'as well as reduces operating costs since by reason of the projecting tubular extension a definite amount of mercury may be introduced into the device by the above described method and the danger of clogging the exhaust valves with mercury removed from the device is avoided.

Although'a preferred embodiment of the invention is shown and described herein it is to be understood that modifications may be made therein without. departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. The method of filling a mercury switch device which comprises providing a bulb with an exhaust tube extending a given diswith the inner end of the exhaust tube uppermost, evacuating the bulb through the exhaust tube, introducing mercury into said bulb to a level above the upper end of the exhaust tube and causing the portion of mercury abovesaid end to flow out of said bulb through said tube While the bulb is supported as above mentioned, so that the length of the extended portion of said exhaust tube will limit the depth of the mercury.

In testimony whereof, I have hereunto subscribed my name this 22nd day of August,

JAMES M. FAGAN. 

